The present invention relates to a compressor, especially for the air-conditioning system of a motor vehicle, having a housing and a compressor unit or pump unit arranged in the housing for drawing in and compressing a coolant.
Compressors of the above described type are generally termed air-conditioning compressors and are known in practice in a large variety of forms. Such compressors comprise a housing which includes a compressor unit or pump unit driven from outside. The pump unit which is in the form, for example, of an axial piston pump in turn comprises at least one piston which is movable to and fro in a cylinder block. Generally, such a compressor is equipped with several pistons which, on rotation of a wobble plate, are moved to and fro in the direction of their longitudinal axis by means of a receiving disc, the receiving disc being mounted in a rotationally secure manner in the housing.
Air-conditioning compressors of the most varied design operate with a coolant, the choice of coolant becoming increasingly problematic from an ecological point of view. In any case, the coolant predominantly used at present is R134a but quite considerable ecological doubts are now being raised about that coolant also.
The compressors known in practice and operating with the coolant R134a generally have a housing which is manufactured from aluminum and which, with a maximum bursting pressure of 8 MPa, has wall thicknesses of approximately from 3 mm to 5 mm.
The air-conditioning compressors known from practice are, however, problematic in that there is an increasing requirement for a 100 % environmentally compatible coolant. As purchasers of motor vehicles become increasingly environmentally-aware, that requirement is coming ever more to the fore.
When the air-conditioning compressor is for use in motor vehicles, there is also a requirement, which is likewise increasing, for a smaller structural size. The structural size of known compressors, however, can hardly be further reduced, especially since a specific heating capacity or cooling capacity of the air-conditioning system and therefore a corresponding volumetric displacement or a corresponding mass flow rate of coolant have to be provided for, which in turn requires a minimum structural size.
An object of the present invention is accordingly to provide a compressor that is suitable for use in the air-conditioning system of a motor vehicle and of a structural size which can be reduced compared with compressors previously known, without reducing the compressor capacity. The use of an ecologically harmless coolant is also to be possible.